System having semiconductor component with multiple stacked dice

ABSTRACT

A system includes a semiconductor component having a base die and a secondary die flip chip mounted to the base die. The base die includes a set of stacking contacts for flip chip mounting the secondary die to the base die, and a set of interconnect contacts configured as an internal signal transmission system, and a physical structure for supporting a terminal contact system of the package component. The component also includes an encapsulant on the base die encapsulating the interconnect contacts, an underfill layer between the dice, and terminal contacts configured for flip chip mounting the package component to a supporting substrate.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of Ser. No. 11/167,031, filed Jun. 27,2005, U.S. Pat. No. 7,335,994 B2, which is a division of Ser. No.10/351,888, filed Jan. 27, 2003.

This application is related to Ser. No. 10/85 1,575, filed May 21, 2003.

FIELD OF THE INVENTION

This invention relates generally to semiconductor manufacture andpackaging. More particularly, this invention relates to semiconductorcomponents having stacked dice, to methods for fabricating thecomponents, and to systems incorporating the components.

BACKGROUND OF THE INVENTION

High speed semiconductor components, such as packages containing digitallogic dice, are typically bumped during manufacture, and then flip chipmounted on a supporting substrate, such as a package substrate, a modulesubstrate or a printed circuit board (PCB). With flip chip mounting,bumps, pins or other terminal contacts on the component, are bonded tomating contacts on the supporting substrate. One well known type of flipchip mounting is known as controlled collapse chip connection (C4).

Flip chip packaging methods are low cost and facilitate the volumemanufacture of semiconductor components, particularly semiconductorpackages. In addition, flip chip packaging methods provide improvedelectrical and thermal performance relative to traditional packagingmethods that employ wire bonding.

As the semiconductor industry advances, manufacturers are developingdifferent packaging methods that make the components smaller, andprovide a more reliable and efficient protective and signal transmissionsystem for the semiconductor dice contained in the components. Onetechnique for expanding the capabilities of a component is toincorporate multiple dice into a single component, such as by stackingtwo or more dice. For example, systems in a package (SIPs), can includedice stacked on a substrate, each of which has a different configuration(e.g., memory vs. processing). The stacked dice provide increasedintegration, security and performance in a component, and decrease theoutline (i.e., footprint) of the component.

One aspect of semiconductor components containing stacked dice is thatthey are typically not fabricated using flip chip packaging methods, anddo not typically include terminal contacts that allow the components tobe flip chip mounted to substrates. It would be desirable to use flipchip packaging methods to fabricate various types of components, such aspackages and modules, which contain stacked dice. In addition, it wouldbe desirable to fabricate various types of components with terminalcontacts that allow flip chip mounting of the components.

The present invention is directed to components containing multiplestacked dice, which are fabricated using flip chip packaging methods andinclude flip chip features. The present invention is also directed towafer level methods for fabricating the components, and to systemsincorporating the components.

SUMMARY OF THE INVENTION

In accordance with the present invention, semiconductor componentshaving stacked dice and flip chip features are provided. Also providedare methods for fabricating the components using wafer level packaging,and systems incorporating the components.

In an illustrative embodiment, a package component includes a pair ofstacked dice including a base die and a secondary die. The base die andthe secondary die can have different electrical configurations such asmemory, processing or an application specific configuration, such thatthe package component can be configured as a system in a package. Inaddition, the base die has a peripheral outline that is larger than thatof the secondary die, and the same as the footprint of the packagecomponent, such that a chip size package can be provided.

The base die includes two sets of contacts including a set of stackingcontacts for flip chip mounting the secondary die to the base die, and aset of interconnect contacts configured as an internal signaltransmission system, and a physical structure for supporting a terminalcontact system of the package component. The package component alsoincludes an encapsulant on the base die encapsulating the interconnectcontacts, an underfill layer between the dice, and terminal contactsconfigured for flip chip mounting the package component to a supportingsubstrate.

The wafer level method for fabricating the package component includesthe steps of providing a base wafer containing a plurality of base dice,and flip chip mounting the secondary dice to the base dice on the basewafer. In addition, the method includes the steps of forming theinterconnect contacts on the base dice, forming an encapsulant on thebase die and the interconnect contacts, and forming underfill layersbetween the base dice and the secondary dice. In addition, the methodincludes the steps of planarizing the secondary dice, the encapsulantsand the interconnect contacts, forming terminal contacts on theplanarized interconnect contacts, and then singulating the base waferinto the package components.

An alternate embodiment package component includes a base die, and atleast two stacked dice including a first secondary die flip chip mountedto the base die, and a second secondary die flip chip mounted to thefirst secondary die. An alternate embodiment module component includestwo or more base dice, and two or more secondary dice flip chip mountedto the base dice.

The package components and the module component can be used to constructvarious electrical systems such as systems in a package (SIPs), modulesystems and computer systems.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an enlarged schematic bottom view of a package componentconstructed in accordance with the invention;

FIG. 1B is a enlarged schematic side elevation view of the packagecomponent;

FIG. 1C is an enlarged schematic cross sectional view of the packagecomponent taken along section line 1C-1C of FIG. 1A;

FIG. 1D is an enlarged schematic cross sectional view of the packagecomponent taken along section line 1D-1D of FIG. 1C;

FIG. 1E is an enlarged schematic cross sectional view of the packagecomponent taken along section line 1E-1E of FIG. 1C;

FIG. 1F is an enlarged schematic cross sectional view of the packagecomponent taken along section line 1F-1F of FIG. 1C;

FIG. 1G is an enlarged schematic cross sectional view taken of thepackage component taken along section line 1G-1G of FIG. 1D;

FIG. 2 is a plan view of a base wafer used in the fabrication of thepackage component;

FIG. 3A is an enlarged schematic cross sectional view of a base die ofthe base wafer taken along section line 3A-3A of FIG. 2;

FIG. 3B is an enlarged schematic cross sectional view of the base waferfollowing an insulating step;

FIG. 4 is a plan view of a secondary wafer used in the fabrication ofthe package component of FIGS. 1A-1C;

FIG. 5A is an enlarged schematic cross sectional view of a secondary dieof the secondary wafer taken along section line 5A-5A of FIG. 4;

FIG. 5B an enlarged schematic cross sectional view of the secondarywafer following an insulating step of the fabrication process;

FIG. 5C an enlarged schematic cross sectional view of the secondarywafer following a bump forming step of the fabrication process;

FIG. 6 is a schematic cross sectional view of the base wafer and thesecondary wafer during a bonding step of the fabrication process;

FIG. 7A is an enlarged schematic cross sectional view of the base waferand the secondary wafer taken along section line 7A of FIG. 6;

FIG. 7B is an enlarged schematic cross sectional view of the base waferand the secondary wafer following the bonding step of the fabricationprocess;

FIG. 7C is an enlarged schematic cross sectional view of the base waferand the secondary wafer following an underfill step of the fabricationprocess;

FIG. 7D is an enlarged schematic cross sectional view of the base waferand the secondary wafer following a bump contact forming step of thefabrication process;

FIG. 7E is an enlarged schematic cross sectional view of the base waferand the secondary wafer following an encapsulating step of thefabrication process;

FIG. 7F is an enlarged schematic cross sectional view of the base waferand the secondary wafer following a thinning step of the fabricationprocess;

FIG. 7G is an enlarged schematic cross sectional view of the base waferand the secondary wafer following a conductor forming step of thefabrication process;

FIG. 7H is an enlarged schematic cross sectional view of the base waferand the secondary wafer following an insulating step of the fabricationprocess;

FIG. 7I is an enlarged schematic cross sectional view of the base waferand the secondary wafer following an external contact bump forming stepof the fabrication process;

FIG. 8A is an enlarged schematic bottom view of an alternate embodimentpackage component having pin contacts;

FIG. 8B is an enlarged schematic side elevation view the alternateembodiment package component;

FIG. 8C is an enlarged cross sectional view of the alternate embodimentpackage taken along section line 8C-8C of FIG. 8A;

FIG. 9A is an enlarged schematic cross sectional view of an alternateembodiment package component containing two or more stacked secondarydice;

FIG. 9B is an enlarged schematic cross sectional view of an alternateembodiment package component having stacked secondary dice and pincontacts;

FIG. 10A is an enlarged schematic bottom view of an alternate embodimentmodule component having two or more base dice and two or more stackeddice on the base dice;

FIG. 10B is an enlarged schematic cross sectional view of the alternateembodiment module component taken along section line 10B-10B of FIG.10A;

FIG. 11A is a schematic plan view of a module system constructed usingthe package component;

FIG. 11B is an enlarged schematic cross sectional view of the modulesystem taken along section line 11B-11B of FIG. 11A;

FIG. 12 is an enlarged schematic cross sectional view of a package in asystem constructed using the package component; and

FIG. 13 is an enlarged schematic cross sectional view of a computersystem constructed using the package component or the module component.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As used herein, the term “semiconductor component” refers to anelectronic element that includes a semiconductor die. Exemplarysemiconductor components include semiconductor packages andsemiconductor modules.

The term “wafer level packaging method” means a semiconductor packagingmethod in which semiconductor wafers are used to make semiconductorcomponents.

Referring to FIGS. 1A-1C, a package component 10 constructed inaccordance with the invention is illustrated. As shown in FIG. 1C, thepackage component 10 includes a base die 12 (first die in some of theclaims), and a secondary die 14 (second die in some of the claims) whichis stacked and flip chip bonded to the base die 12. The packagecomponent 10 also includes an encapsulant 16 formed on the base die 12and on the edges of the secondary die 14.

The package component 10 also includes an array of electricallyconductive terminal contacts 18 configured for signal transmission toand from the package component 10. In the illustrative embodiment theterminal contacts 18 comprise metal bumps or balls. However, theterminal contacts 18 can also comprise pins, polymer bumps, springcontacts or any terminal contact known in the art. Also in theillustrative embodiment, there are eighteen terminal contacts 18,arranged in a peripheral array. However, this arrangement is merelyexemplary, and the terminal contacts 18 can be arranged in any densearea array, such as a ball grid array (BGA), or a fine ball grid array(FBGA).

The base die 12 and the secondary die 14 can comprise conventionalsemiconductor dice having a desired configuration. For example, each die12, 14 can comprise a high speed digital logic device, such as a dynamicrandom access memory (DRAM), a static random access memory (SRAM), aflash memory, a microprocessor, a digital signal processor (DSP) or anapplication specific integrated circuit (ASIC). In addition, each die12, 14 can have a different configuration. For example, the base die 12can comprise an application specific device, and the secondary die 14can comprise a memory device. The package component 10 can thus beconfigured as a system in a package (SIP).

The base die 12 has a peripheral outline (footprint) that is identicalto the peripheral outline (footprint) of the package component 10. Thepackage component 10 can thus be considered a chip scale package (CSP).In addition, the peripheral outline of the base die 12 is larger thanthe peripheral outline of the secondary die 14. In the illustrativeembodiment, the base die 12, the secondary die 14 and the packagecomponent 10 all have generally rectangular peripheral outlines, butother polygonal outlines, such as square or hexagonal can also beutilized.

As shown in FIG. 1C, the base die 12 has a circuit side 24 and a backside 26. The circuit side 24 includes active semiconductor devices andintegrated circuits 36 (FIG. 1G) fabricated using techniques that arewell known in the art. The circuit side 24 of the base die 12 faces thesecondary die 14, and the back side 26 of the base die 12 forms anoutside surface of the package component 10.

As shown in FIG. 1D, the base die 12 includes a set of stacking contacts20 (first contacts in some of the claims) on the circuit side 24, whichare configured for stacking the secondary die 14 on the base die 12using flip chip bonding techniques. The base die 12 also includes a setof interconnect contacts 22 (second contacts in some of the claims) onthe circuit side 24 in electrical communication with the first contacts20. The base die 12 also includes patterns of conductors 28 configuredto establish electrical communication between the stacking contacts 20and the interconnect contacts 22.

As shown in FIG. 1G, the conductors 28 also establish electricalcommunication between the interconnect contacts 22 and the integratedcircuits 36 contained on the base die 12. In the illustrativeembodiment, the conductors 28 are formed on a die passivation layer 38of the base die 12 in electrical communication with die contacts 32,such as the device bond pads for the base die 12. In addition, internalconductive traces 34 in the base die 12 complete the electrical pathbetween the integrated circuits 36 and the interconnect contacts 22. Aswill be further explained, the conductors 28 can comprise aredistribution layer (RDL) formed using a subtractive process (e.g.,etching) or an additive process (e.g., sputtering, or a combination ofsputtering and plating) as is known in the art.

As also shown in FIG. 1G, the base die 12 includes an insulating layer30 configured to electrically insulate and protect the conductors 28.The insulating layer 30 also seals and protects the circuit side 24 ofthe base die 12. The insulating layer 30 can comprise a polymer, such aspolyimide or BCB, an oxide such as silicone dioxide, or a glass, such asborophosphosilicate glass (BPSG). In addition, the insulating layer 30includes openings 40 aligned with the interconnect contacts 22, and alsowith the stacking contacts 20.

Referring again to FIG. 1C, the secondary die 14 includes a circuit side46 and a thinned back side 48. The circuit side 46 of the secondary die14 faces the base die 12, and the thinned back side 48 forms an outsidesurface of the package component 10. The secondary die 14 also includesbumped contacts 44 bonded to the stacking contacts 20 on the base die12. In the illustrative embodiment the bumped contacts 44 comprise metalbumps or balls. However, the bumped contacts 44 can also comprise metalpins, conductive polymer bumps or other types of raised contacts thatare known in the art. As shown in FIG. 1E, the bumped contacts 44 on thesecondary die 14 have a grid pattern that exactly matches a grid patternof the stacking contacts 20 (FIG. 1D) on the base die 12. However, thegrid patterns need not match exactly, as some of the stacking contacts20 may not have a corresponding bumped contact 44, and some of thebumped contacts 44 may not have a corresponding stacking contact 20.

In addition, the secondary die 14 includes conductors 42 on the circuitside 46 configured to establish electrical communication between thebumped contacts 44 and the integrated circuits contained on thesecondary die 14, substantially as previously described for theconductors 28 (FIG. 1G) on the base die 12. The secondary die 14 alsoincludes an insulating layer 50 which electrically insulates theconductors 42 and the circuit side 46 of the secondary die 14.

As also shown in FIG. 1C, the package component 10 includes bumpedinterconnect contacts 52 bonded to the interconnect contacts 22 on thebase die 12, and embedded in the encapsulant 16 for the packagecomponent 10. In the illustrative embodiment the bumped interconnectcontacts 52 comprise metal bumps or balls. However, the bumpedinterconnect contacts 52 can also comprise metal pins, conductivepolymer bumps or other types of raised contacts that are known in theart.

As shown in FIG. 1E, the encapsulant 16 has a picture frame shape, withan outside peripheral shape that matches the base die 12, and an insideperipheral shape that matches the secondary die 14. Stated differently,the encapsulant is contained on the base die 12 in an area bounded bythe peripheral outline of the secondary die 14 and the peripheraloutline of the base die 12.

The encapsulant 16 can comprise a polymer material such as an epoxy, asilicone, a polyimide or a transfer molded underfill compound (MUF). Inaddition, these polymer materials can include fillers such as silicatesconfigured to reduce the coefficient of thermal expansion (CTE) andadjust the viscosity of the polymer material. The encapsulant 16 canalternately comprise a laser imageable material, which can be patternedusing a stereographic lithography process to be hereinafter described.

As also shown in FIG. 1C, the package component 10 includes an underfilllayer 54 that helps to bond the secondary die 14 to the base die 12, tofill the space therebetween and to absorb thermal stresses. Theunderfill layer 54 can comprise a conventional underfill polymer such asa curable silicone, epoxy or polyimide material. The underfill layer 54can also comprise a thermoset polymer underfill film, such as anunderfill film manufactured by 3M Corporation of Minneapolis, Minn.

As shown in FIG. 1F, the thinned back side 48 (FIG. 1C) of the secondarydie 14 includes an array of terminal contact pads 56 wherein theterminal contacts 18 (FIG. 1C) are bonded. The thinned back side 48 canalso include an insulating layer 58 having openings aligned with theterminal contact pads 56. In the illustrative embodiment, the terminalcontact pads 56 have a peripheral pattern that matches the peripheralpattern of the bumped interconnect contacts 52. However, thisarrangement is merely exemplary and other area arrays for the terminalcontacts 18, such as a ball grid array (BGA) or fine ball grid array(FBGA) can be employed. For example, as shown by the dashed lines inFIG. 1F, additional BGA terminal contact pads 60 and BGA conductors 62can be employed to form a ball grid array of terminal contacts 18(second terminal contacts in some of the claims) on the thinned backside 48 of the secondary die 14. In this case an additional insulatinglayer (not shown) can be formed on the thinned base side 48 forelectrically insulating the terminal contact pads 60 and the BGAconductors 62 from the bulk silicon.

As also shown in FIG. 1F, additional electrical elements 88, such as oneor more capacitors, and conductors 90 electrically connecting theelectrical elements 88 to the terminal contact pads 56, can also beformed on, or mounted to, the circuit side 24 of the base die 12. Inaddition, the electrical elements 88 can be embedded in the encapsulant16 (FIG. 1C). For example, surface mount capacitors having an extremelysmall height (e.g., 11 mils) are commercially available from AVXCorporation of Myrtle Beach, S.C. One suitable capacitor is a #0201 fromAVX. This type of capacitor is useful for reducing noise in the packagecomponent 10P. Other manufacturers of electrical elements such ascapacitors include Taiyo, Yuden and Murata.

Referring to FIGS. 2, 3A and 3B, initial steps in a method forfabricating the package component 10 are illustrated. Initially, asshown in FIG. 2, a base wafer 64 containing a plurality of base dice 12is provided. As shown in FIG. 3A, the stacking contacts 20, theinterconnect contacts 22 and the conductors 28 are formed on the circuitside 24 of each die 12 in electrical communication with the die contacts32 (FIG. 1G) and integrated circuits 36 (FIG. 1G) on the die 12.

The stacking contacts 20, the interconnect contacts 22 and theconductors 28 can be formed on the circuit sides 24 of the base dice 12using known techniques, such as deposition and patterning of one or moreredistribution layers in electrical communication with the die contacts32 (FIG. 1G) for the base dice 12. Redistribution layers are widely usedin semiconductor manufacture to customize the signal transmitting andterminal contact configuration of dice having standardized bond padconfigurations. One suitable redistribution process is described in U.S.Pat. No. 5,851,911 to Farnworth, which is incorporated herein byreference. Alternately, rather than forming the stacking contacts 20,the interconnect contacts 22 and the conductors 28 from a redistributionlayer, the base dice 12 and the base wafer 64 can be custom fabricatedwith these features. As another alternative, the stacking contacts 20,the interconnect contacts 22 and the conductors 28 can comprise a tapematerial such as TAB tape or ASMAT available from Nitto DenkoCorporation of Japan.

Following forming (or providing) of the stacking contacts 20, theinterconnect contacts 22 and the conductors 28, the insulating layers 30are formed on the circuit sides 24 of the base dice 12. The insulatinglayers 30 cover the conductors 28 on each base die 12, but include theopenings 40 aligned with the stacking contacts 20 and the interconnectcontacts 22 on each base die 12. The insulating layers 30 can comprise apolymer, such as polyimide or BCB, an oxide such as silicon dioxide, ora glass, such as borophosphosilicate glass (BPSG) formed usingtechniques that are known in the art, such as by blanket deposition ontothe base wafer 64 to a desired thickness. In addition, the openings 40can be formed in the insulating layers 30 using known techniques, suchas by patterning and developing a photoimageable mask material and thenetching through the mask material. As another alternative, theinsulating layers 30 can comprise a photoimageable material such as aresist or a photoimageable polyimide. A representative thickness of theinsulating layers 30 formed of a polymer can be from about 1 mil (25.4μm) to about 12 mils (304.8 μm).

Referring to FIGS. 4, 5A, 5B and 5C, further initial steps forfabricating the package component 10 are illustrated. As shown in FIG.4, a secondary wafer 66 containing a plurality of secondary dice 14 isprovided. As shown in FIG. 4A, the conductors 42, and bumped contactpads 68 for the bumped contacts 44 (FIG. 5C), are formed on the circuitside 46 of each secondary die 14 in electrical communication with thedie contacts 32 (FIG. 1G) and integrated circuits 36 (FIG. 1G) on thedie 14.

The conductors 42, and the bumped contact pads 68, can be formed on thecircuit sides 46 of the secondary dice 14 using known techniques, suchas deposition and patterning of one or more redistribution layerssubstantially as previously described for the stacking contacts 20, theinterconnect contacts 22 and the conductors 28 on the base dice 12. Asalso previously described, rather than using a redistribution layer, thesecondary dice 14 can be provided with the conductors 42 and the bumpedcontact pads 68. As also shown in FIG. 5A, the back sides 72 of thesecondary dice 14 are not processed, but will subsequently be ground, orpolished, to form the thinned back sides 48 (FIG. 1C) of the secondarydice 14.

Next, as shown in FIG. 5B, the insulating layers 50 are formed on thecircuit sides 46 of the secondary dice 14. The insulating layers 50cover the conductors 42 on each secondary die 14, but include openings70 aligned with the bumped contact pads 68 on each secondary die 14. Theinsulating layers 50 can comprise a polymer, such as polyimide or BCB,an oxide such as silicon dioxide, or a glass, such asborophosphosilicate glass (BPSG), formed using techniques that are knownin the art, such as by blanket deposition onto the secondary wafer 66 toa desired thickness and then etching, substantially as previouslydescribed for insulating layer 30 (FIG. 3B) and openings 40 (FIG. 3B).

Next, as shown in FIG. 5C, the bumped contacts 44 are formed on thebumped contact pads 68. This step can be performed by bonding, ordepositing, the bumped contacts 44 on the bumped contact pads 68. Forexample, the bumped contacts 44 can comprise metal bumps deposited usinga suitable deposition process, such as stenciling and reflow of a solderalloy. Also, rather than being formed of solder, the bumped contacts 44can comprise another metal, or a conductive polymer material.

The bumped contacts 44 can also be formed by electrolytic deposition, byelectroless deposition, or by bonding pre-fabricated balls to the bumpedcontact pads 68. A ball bumper can also be employed to bondpre-fabricated balls. A suitable ball bumper is manufactured by Pac TechPackaging Technologies of Falkensee, Germany. The bumped contacts 44 canalso be formed using a conventional wire bonder apparatus adapted toform a ball bond on the bumped contact pads 68, and then to sever theattached wire. Still further, the bumped contacts 44 can comprise metalor metal plated pins formed on, or bonded to, the bumped contact pads68.

Following formation of the bumped contacts 44, the base wafer 64 issingulated (diced) into the individual secondary dice 14. Thesingulating step can be performed using a sawing method or anothersingulation method, such as cutting with a laser or a water jet, or beetching the secondary wafer 66 with a suitable wet or dry etchant.

Next, as shown in FIG. 6, the singulated secondary dice 14 are placed onthe base dice 12 contained on the base wafer 64. The secondary dice 14can be placed on the base dice using conventional equipment, such as avacuum pick and place mechanism, or an aligner bonder under computercontrol. As shown in FIG. 7A, the secondary dice 14 are placed on thebase dice 12 with the bumped contacts 44 on the secondary dice 14aligned, and in physical contact with the stacking contacts 20 on thebase dice 12.

However, prior to placing the secondary dice 14 on the base dice 12,each secondary die 14 can optionally be individually tested usingtechniques that are known in the art. Testing of the secondary dice 14can be as desired, from gross functionality testing to certification asa known good die (KGD). For example, testing can include any test usedin the industry, including but not limited to: gross functionalitytesting, cell defect testing, opens testing, shorts testing, pad leakagetesting, parametric testing, and burn-in testing.

Next, as shown in FIG. 7B, following the secondary die placing step, thebumped contacts 44 on the secondary dice 14 are bonded to the stackingcontacts 20 on the base dice 12. If the bumped contacts 44 are formed ofsolder, or another metal, the bonding step can be performed by heatingand reflowing the bumped contacts 44 to form metallurgical bonds withthe stacking contacts 20. If the bumped contacts 44 are formed of aconductive polymer, other bonding techniques, such as chemical reaction,or UV curing, can be employed. If the bumped contacts 44 comprise metalor metal plated pins a welding, soldering or brazing process can beemployed.

Next, as shown in FIG. 7C, the underfill layer 54 is formed between thesingulated secondary dice 14 and the base dice 12 contained on the basewafer 64. The underfill layer 54 can comprise a conventional underfillpolymer such as a curable silicone, epoxy or polyimide material. Theunderfill layer 54 can also comprise a thermoset polymer underfill film,such as an underfill film manufactured by 3M Corporation of Minneapolis,Minn. The underfill layer 54 can be formed using a conventional processsuch as by injection of a curable material in the spaces between thesecondary dice 14 and the base dice 12. In this case a “wicking” or“capillary” underfill material can be employed. Alternately, a “no flow”underfill material can be placed on either of the circuit sides 24 or 46of the secondary dice 14 or the base dice 12, prior to the bonding step.

Next, as shown in FIG. 7D, the bumped interconnect contacts 52 areformed on the base dice 12 contained on the base wafer 64. The bumpedinterconnect contacts 52 can be formed on the interconnect contacts 22of solder, another metal or a conductive polymer, using a deposition orbonding process, substantially as previously described for the bumpedcontacts 44 on the secondary dice 14. The bumped interconnect contacts52 can also comprise metal or plated metal pins bonded to theinterconnect contacts 22 using a bonding process such as welding,soldering or brazing.

The diameter D of the bumped contacts 44 can be selected as requiredwith a range of about 0.005-in (0.127 mm) to about 0.016-in (0.400 mm),or larger, being representative. As shown in FIG. 7D, the bumpedinterconnect contacts 52 can have a diameter D, that is less than theheight H of the back side 72 of the secondary die 14 measured from thesurface of the base die 12. As will be further explained, the bumpedinterconnect contacts 52 and the secondary die 14 will be planarized sothat the surfaces of the bumped interconnect contacts 52 aresubstantially planar to the thinned back side 48 of the secondary die14.

Next, as shown in FIG. 7E, the encapsulants 16 are formed on the basedice 12 contained on the base wafer 64. Each encapsulant 16 has apicture frame outline, substantially as previously described and shownin FIG. 1E. The encapsulants 16 function to electrically insulate andencapsulate the bumped interconnect contacts 52. In addition, theencapsulants 16 function to at least partially encapsulate or pot thesecondary dice 14 to the base dice 12. Further, the encapsulants 16function to at least partially support the terminal contacts 18.

Following a base wafer 64 singulating step to be hereinafter described,the peripheral edges 76 of the encapsulant 16 will be substantiallyplanar to the peripheral edges 78 of the base die 12 to which it isattached. Further, each encapsulant 16 substantially covers a pictureframe shaped area on the base die 12 bounded by the peripheral edges ofthe secondary die 14, and the peripheral edges 78 of the base die 12.

The encapsulants 16 can comprise an epoxy, a silicone, a polyimide or atransfer molded underfill compound (MUF) having selected fillers. Onesuitable curable polymer material is manufactured by Dexter ElectronicMaterials of Rocky Hill, Conn. under the trademark “HYSOL” FP4450. Inaddition, each encapsulant 16 can be formed with a desired thickness andshape using a suitable deposition process, such as deposition through anozzle, screen printing, stenciling, stereographic lithography ortransfer molding.

For example, a nozzle deposition apparatus, such as a materialdispensing system, manufactured by Asymtek of Carlsbad, Calif., can beused to form the encpasulants 16. Following deposition, the encapsulants16 can be cured to harden. Curing of the above identified polymermaterial can be performed by placement of the base wafer 64 in an ovenat a temperature of about 90° to 165° C. for about 30 to 60 minutes.

With stereo lithography the encapsulants 16 can comprise a laserimageable material, such as a Cibatool SL 5530 resin manufactured byCiba Specialty Chemicals Corporation. In this case, the laser imageablematerial can be patterned and developed using a laser beam to provide anexposure energy. A stereo lithography system for performing the processis available from 3D Systems, Inc. of Valencia, Calif. In addition, astereographic lithographic process (3-D) is described in U.S.application Ser. No. 09/259,142, U.S. Pat. No. 6,549,821, to Farnworthet al. filed on Feb. 26, 1999, and in U.S. application Ser. No.09/652,340, U.S. Pat. No. 6,544,902, to Farnworth et al. filed on Aug.31, 2000, both of which are incorporated herein by reference.

Following formation of the encapsulants 16 and as shown in FIG. 7F, aplanarizing step is performed in which the encapsulants 16 areplanarized to expose planar contact surfaces 80 on the bumpedinterconnect contacts 52. In addition, the planarizing step can beperformed such that the secondary dice 14 are thinned and planarized aswell. As with the previous steps, the planarizing step is performed withthe base dice 12 still contained on the base wafer 64, and the secondarydice 14 attached to the base dice 12. The planarizing step forms aplanarized surface 74 that includes the planar contact surfaces 80 onthe bumped interconnect contacts 52, and the thinned back side 48 of thesecondary dice 14.

The planarizing step can be performed using a mechanical planarizationapparatus (e.g., a grinder). One suitable mechanical planarizationapparatus is manufactured by Okamoto, and is designated a model no.VG502. Another suitable mechanical planarization apparatus ismanufactured by Accretech USA Inc., of Oakland, N.J. and is designated amodel PG300RM wafer thinning system. The planarizing step can also beperformed using a chemical mechanical planarization (CMP) apparatus. Asuitable CMP apparatus is commercially available from a manufacturersuch as Westech, SEZ, Plasma Polishing Systems, or TRUSI. Theplanarizing step can also be performed using an etch back process, suchas a wet etch process, a dry etch process or a plasma etching process.

By way of example and not limitation, the planarizing step can beperformed such that the secondary dice 14 are thinned to a thickness ofabout 1 mil (25.4 μm) to about 27 mils (685.8 μm). However, although theplanarizing step is illustrated as thinning the secondary dice 14, thediameter D (FIG. 7D) of the bumped interconnect contacts 52 can beselected such that the secondary dice 14 are not thinned. For example,the diameter D can be approximately equal to, or slightly greater than,the height H of the secondary dice 14 on the base wafer 64. Theplanarizing step could then be end pointed at the back sides 72 of thesecondary dice 14 such that the secondary dice 14 have a standardthickness (e.g., 28 mils).

Following the planarizing step, and as an optional additional step, eachbase die 12 and associated secondary die 14 can be tested using theplanar contact surfaces 80 on the bumped interconnect contacts 52 asaccess points. For example, simple continuity tests can be performed toevaluate the electrical paths between the attached pairs of base dice 12and secondary dice 14.

Next, as shown in FIG. 7G, the terminal contact pads 56 can be formed onthe planar contact surfaces 80 of the bumped interconnect contacts 52.However, this step is optional, as for some applications, the terminalcontacts 18 can be formed directly on the planar contact surfaces 80.The terminal contact pads 56 can be formed using known techniques, suchas by deposition and patterning of one or more redistribution layers,substantially as previously described for the stacking contacts 20, theinterconnect contacts 22 and the conductors 28 on the base dice 12. Inaddition, the BGA terminal contact pads 60 (FIG. 1F) and the BGAconductors 62 (FIG. 1F) can also be formed at the same time to provide agrid array. The terminal contact pads 56 can also comprise a performedtape material such as TAB tape or ASMAT manufactured by Nitto DenkoCorp. of Japan.

Next, as shown in FIG. 7H, the insulating layer 58 can be formed whileleaving the terminal contact pads 56 exposed. Again this step isoptional as for some applications the insulating layer 58 will not benecessary. One such application may be where the terminal contacts 18are formed directly on the planarized contact surfaces 80 of the bumpedinterconnect contacts 52. The insulating layer 58 can be formedsubstantially as previously described for the insulating layers 30 (FIG.3B) and 50 (FIG. 5B).

Next, as shown in FIG. 7I, the terminal contacts 18 can be formed on theterminal contact pads 56. The terminal contacts 18 can comprise solder,metal, or a conductive polymer formed using a deposition or bondingprocess substantially as previously described for the bumpedinterconnect contacts 52 on the base dice 12, and the bumped contacts 44on the secondary dice 14. As will be further explained, the terminalcontacts 18 allow the package component 10 to be flip chip mounted tomating contacts on a supporting substrate. The terminal contacts 18 canalso comprise metal pins or plated metal pins formed using a bondingprocess such as welding, soldering or brazing. As another alternativethe terminal contacts 18 can comprise spring contact pins as describedin U.S. Pat. No. 5,495,667 to Farnworth et al., which is incorporatedherein by reference.

Referring to FIGS. 8A, 8B and 8C an alternate embodiment packagecomponent 10P is illustrated. The package component 10P is identical tothe previously described package component 10 (FIGS. 1A-1G) but includespin terminal contacts 18P rather than terminal contacts 18 (FIG. 1A).The pin terminal contacts 18P can be formed by soldering, brazing orwelding pins to the terminal contact pads 56 (FIG. 1C). Alternately thepin terminal contacts 18P can be formed by wire bonding and thensevering wires to a selected length. In addition, as illustrated by thedashed lines in FIG. 8A, the pin contacts 18P can be formed in a pingrid array (PGA) substantially as previously described for the terminalcontacts 18 in a ball grid array (BGA).

In addition to the pin terminal contacts 18P, the package component 10Pincludes pin interconnect contacts 52P, in place of the bumpedinterconnect contacts 52 (FIG. 1C) on the base die 12. In addition, thepackage component 10P includes pin contacts 44P on the secondary die 14in place of the bumped contacts 44.

Referring to FIG. 9A, an alternate embodiment package component 10S isillustrated. The package component 10S includes the base die 12, aspreviously described, and two stacked, thinned secondary dice: includinga first secondary die 14-1 flip chip mounted to the base die 12, and asecond secondary die 14-2 flip chip mounted to the second secondary die14-2. In addition, the first secondary die 14-1 includes bumped contacts44 bonded to the interconnect contacts 22 on the base die 12, aspreviously described. The first secondary die 14-1 also includes anadditional insulating layer 86 formed on the back side thereof, and anadditional metallization layer comprising a pattern of conductors 110and contact pads 114 configured for flip chip mounting the secondsecondary die 14-2 to the first secondary die 14-1.

The base die 12 of the package component 10S also includes anencapsulant 16 as previously described, and the conductors 110 are alsoformed on the encapsulant 16. In addition, the base die 12 includesbumped interconnect contacts 52, an additional set of bumpedinterconnect contacts 118 on the bumped interconnect contacts 52, and anadditional encapsulant 120 formed on the bumped contacts 118,substantially as previously described for encapsulant 16. The packagecomponent 10S also includes terminal contact pads 56 and terminalcontacts 18 bonded to the terminal contacts pads 56 as previouslydescribed. As with the previous embodiments, the base die 12, the firstsecondary die 14-1, and the second secondary die 14-2 can be configuredand electrically interconnected such that the package component 10Sforms a system in a package.

Referring to FIG. 9B an alternate embodiment package component 10SP issubstantially identical to the package component 10S but includes pininterconnect contacts 52P in place of bumped interconnect contacts 52,and pin interconnect contacts 118P in place of bumped interconnectcontacts 118. In addition, the package component 10SP includes pincontacts 44P in place of bumped contacts 44 on the stacked dice 14-1,14-2.

Referring to FIGS. 10A and 10B, an alternate embodiment module component10M is illustrated. The module component 10M is substantially identicalto the previously described package component 10, but includes multiplebase dice 12A, 12B, and multiple secondary dice 14A, 14B flip chipmounted to the base dice 12A, 12B. In the illustrative embodiment thereare two base dice 12A which comprise a segment of a base wafer, and twosecondary dice 14B. However, more than two base dice 12A, 12B and morethan two secondary dice 14A, 14B can be used. Further, secondary dice14A, 14B do not necessarily need to be flip chip mounted to the basedice 12A, 12B but can alternately be mounted to pads and conductors inelectrical communication with the base dice 12A, 12B. In addition, themodule component 10M includes a pattern of terminal contacts 18 formedalong the outer periphery thereof, substantially as previouslydescribed.

Referring to FIGS. 11A and 11B, a multi chip module system 92 thatincludes multiple package components 10, 10P or 10S is illustrated. Themulti chip module system 92 can be configured for performing a specificfunction such as memory storage. The multi chip module system 92includes a module substrate 98 having patterns of electrodes 100configured for flip chip mounting the package components 10, 10P or 10Sto the module substrate 98. The terminal contacts 18 on the packagecomponents 10, 10P or 10S can be bonded to the electrodes 100 on themodule substrate 98 using a suitable bonding process, such as solderreflow, thermode bonding or conductive polymer bonding. The electrodes100 are in electrical communication with conductors 94 formed on themodule substrate 98 in a required circuit pattern. In addition, theconductors 94 are in electrical communication with an edge connector 96which provides a connection point from the outside to the multi chipmodule system 92.

Referring to FIG. 12, a system in a package 102 (SIP) that includesmultiple package components 10, 10P or 10S is illustrated. The system ina package 102 can be configured to perform a desired electrical functionsuch as micro processing. In addition, each package component 10, 10P or10S can have a different electrical configuration, such as a microcontroller, a microprocessor or a flash memory. The system in a package102 includes a package substrate 120 wherein the package components 10,10P or 10S are flip chip mounted. The package substrate 120 alsoincludes electrodes and conductors (not shown) which electricallyconnect the package components 10, 10P or 10S in a required electricalconfiguration. The package substrate 120 also includes package leads 106in electrical communication with the package components 10, 10P or 10S.The system in a package 102 also includes a package body 104 formed of amolded plastic, or other suitable material, which encapsulates thepackage substrate 120 and the package components 10, 10P or 10S.

Referring to FIG. 13, a computer system 108 includes one or more packagecomponents 10, 10P or 10S, or the module component 10M which can bemounted to the computer system 108 in a suitable manner. In addition,the package components 10, 10P or 10S, or the module component 10M canbe configured to perform a desired function in the computer system 108such as memory storage or micro processing.

Thus the invention provides improved semiconductor components, methodsfor fabricating the components, and systems incorporating thecomponents. While the invention has been described with reference tocertain preferred embodiments, as will be apparent to those skilled inthe art, certain changes and modifications can be made without departingfrom the scope of the invention as defined by the following claims.

1. A system comprising: a substrate having a plurality of electrodes; atleast one semiconductor component on the substrate comprising a base diehaving a plurality of interconnect contacts, a thinned first secondarydie stacked on the base die comprising a plurality of bumped contactsbonded to the interconnect contacts on the base die and plurality ofcontact pads in electrical communication with the bumped contacts, athinned second secondary die flip chip bonded to the contact pads havinga plurality of terminal contact pads, and a plurality of terminalcontacts on the terminal contact pads in electrical communication withthe electrodes on the substrate; a first encapsulant on the base die atleast partially encapsulating the interconnect contacts; and a secondencapsulant on the first encapsulant having an outside surface whichwith a backside of the second secondary die forms a planar surface forthe terminal contact pads.
 2. The system of claim 1 wherein the base diecomprises an application specific device and the first secondary die andthe second secondary die comprise memory devices.
 3. The system of claim2 wherein the first encapsulant and the second encapsulant comprise acurable polymer, a laser imageable polymer or a photo imageable polymer.4. A system comprising: a substrate having a plurality of electrodes; atleast one semiconductor component on the substrate comprising a base diehaving a plurality of interconnect contacts, a thinned first secondarydie stacked on the base die comprising a plurality of bumped contactsbonded to the interconnect contacts on the base die and plurality ofcontact pads in electrical communication with the bumped contacts, athinned second secondary die flip chip bonded to the contact pads havinga plurality of terminal contact pads, and a plurality of terminalcontacts on the terminal contact pads in electrical communication withthe electrodes on the substrate; a first encapsulant on the base die atleast partially encapsulating the interconnect contacts; a secondencapsulant on the first encapsulant having an outside surface whichwith a backside of the second secondary die forms a planar surface forthe terminal contact pads; and a plurality of conductors on the planarsurface in electrical communication with the terminal contact pads. 5.The system of claim 4 wherein the substrate includes a plurality ofleads in electrical communication with the electrodes.
 6. The system ofclaim 4 wherein the base die and the first secondary die have differentelectrical configurations.
 7. The system of claim 4 wherein thesubstrate is contained in a computer.
 8. The system of claim 4 whereinthe substrate comprises a multi chip module substrate.